Dialogic Voice Cards - JCT Softfax Channel Utilization

Issue

For the Dialogic® JCT series Media Boards, the documentation does not specify which channels are enabled for DSP-Based Fax capability.

Solution

The chart below specifies the number of channels enabled for fax capability, and lists the specific channels that can be used for sending/receiving faxes.

Dialogic JCT series Media Boards configured to use the spfax.fwl firmware will have from 2 to 8 fax resource channels enabled. The following table shows information regarding the boards and channels that support DSP-Based Fax: 

Please click on the following image to display it full size:

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The following table shows the data transmission and reception encoding schemes that can be used with the basic and enhanced fax feature:

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Workaround

The dx_getfeaturelist() api must be used with caution. All capable fax devices (those shown in ‘gray’ boxes in the chart above) will have the feature, as copied from the Voice API Library Reference:

FT_FAX_EXT_TBL – specifies send fax and receive fax feature support.

On JCT series boards, if this bit is turned on and the T_SENDFAX_TXFILE_ASCII bit (in ft_send) is turned on, then the device supports DSP Fax (also known as Softfax).

However the application must still be coded to consider the limitation, so that even though, for example, all 12 devices will have the shared resource feature FT_FAX_EXT_TBL, only 4 fax devices can be used at once; and more specifically, only 2 fax devices can be used within the first eight channels plus another 2 fax devices on the remaining four channels. Similar restrictions will apply to all the other devices listed, except for the D/41JCT-LS and the VFX/41JCT-LS.

Product List

Dialogic JCT series Media Boards, including: 

• D/41JCT-LS 

• VFX/41JCT-LS* 

• D/120JCT-LS 

• D/42JCT-U 

• D/82JCT-U 

• D/240JCT 

• D/300JCT 

• D/480JCT-2T1 

• D/600JCT-2E1